Question

若x²-9分之6x=（x+3分之A）+（x-3)分之B,则A=?B=?

Answer 1

右边通分=[A(x-3)+B(x+3)]/(x+3)(x-3)

=[(A+B)x+(3B-3A)]/(x²-9)

=6x/(x²-9)

所以(A+B)x+(3B-3A)=6x

所以A+B=6

3B-3A=0,即B-A=0

所以A=3,B=3